Casein paint



Patented Jan. 10, 1939 UNITED STATES PATENT OFFICE No Drawing.Application May 28, 1937-, Serial No. 145,383

2 Claims.

My invention relates to paints and processes 'to compound the same, andmore particularly to paints in which the dispersion of casein in analkaline solution forms the vehicle for the pigments, and my main objectis to compound'a paint of this nature which is stable and retains itsadhesive qualities.

A further object of the invention is to employ an improved formula forcompounding paints with a casein content, whereby to render the paintcoating or film immune tohydrolization and consequent decomposition, andso enable it to retain its firm and integral state.

Another object of the invention is to employ a novel process to compoundthe paint, whereby to enable a hydro-carbon to be joined as a cofactorwith the casein and form a preservative for the resulting product.

In the conventional practice of compounding paints with a casein factor,an aqueous alkaline solution for the dispersion of the casein, isconsidered a good vehicle for carrying the paint pigments. However,paints so compounded have proved unstable whenever exposed to moist air,

due to chemical changes occasioned in the casein vehicle by theabsorption of moisture. Thus, the casein dispersion becomes completelyhydrolized in time. and the paint coating or film softens, disintegratesand separates from the surface which it coats.

One method commonly used for fortifying paints prepared with casein isby the admixture of drying oils. While these improve and immunize theproduct to chemical hydrolysis, they cause poor adhesion of the paintcoating to surfaces which are damp; also, the oils impart a glazed orshiny finish to the paint coating which lends glare and harshness ,tolight in contrast with less lustrous finishes, and is therefore lessdesirable.

So far, no standard casein paint compound meets all requirements, and ithas therefore been my intention to develop a paint compound whichremains stable and permanent under all atmospheric conditions.

In accordance with the foregoing, my preferred formula for compoundingthe novel paint is as follows, on a quantitative basis:-

Parts Casein, finely ground 10 Borax, finely ground -s 2 Pigments,finely ground 85 Aluminum stearate, finely ground 1 Water 50 5B Toluol 2ents to produce the novel paint are of essential The above formula isnot critical as to the quantities of the ingredients, althoughexperiments have proved that the proportions given result in a superiorproduct. Neither is the formula limited to the specific substances.Thus, C any mild alkaline salt may replace the borax. The pigment may belithopone or the like. The aluminum stearate may be replaced by anyother water-insoluble metallic soap of stearic, palmitic or other fattyacids. And a hydrocarbon such 10 an xylol may be substituted for thetoluol.

The above ingredients may be compounded by first mixing the powderedingredients-casein, borax and pigments-into the water in a closedvessel, and then passing. the toluol in vaporized 15 form into thevessel, to condense'and produce the solvency action. A good paintproduct is obtained by this method.

Another method of compounding the above ingredients utilizes a closedvessel provided with 99 a strong agitator and jacketed with heatingcoils.

The powdered ingredients are first introduced,

and, the water added as the agitators operate, until the mass attains atemperature of 80 degrees centigrade or slightly higher. Then, as thestirring continues the hydrocarbon toluol or xylol is introduced in theproper proportion, until the contents reach the finishing stage, forminga product of good quality.

A third method for compounding the ingredi- 30 ents utilizes the waterin the form of wet steam. Thus, the dry ingredients are placed, asbefore, in a closed vessel equipped with strong agitators and jacketedwith heating coils; and a condensing coil is provided, to return vaporsto the yes- 35 sel in condensed or liquid form. Now, while theagitators, heating coils and condenser are in action the required amountof the toluol or other hydrocarbon is introduced and followed by thecontinuous injection of live or wet steam until 40 the vessel contentsunder agitation have reached the desired volume. A superior paintproduct is obtained by this method.

The values contributed by the above ingrediimportance. Thus, the caseinforms a binder and substitute for theusual drying oil vehicle. The boraxpromotes the dispersion of the casein. The metallic soap functions as awater resistant and 50 commingles with the molecules of the paint pigments to immunize them from hydrolization. The water provides therequisite consistency. The toluol isa selective solvent for the metallicstearates and creates a solution which more readily penetrates thecompound and envelopes the pigment particles.

It will be evident from the above description that I have improved themanufacture of paints by utilizing the excellent emulsifying property ofcasein when properly dispersed in a water vehicle. I can thus comminglethe hydrocarbon and metallic soap thoroughly with the casein dispersionand produce a paint which has body, adhesive quality, endurance andimmunity to hydrolization.

I claim:

1. A casein paint composition comprising water as a vehicle, a quantityof pigment in excess by weight of the amount of water, casein dispersedin the water, a small amount of dissolved alkaline agent to maintaindispersion of the casein, the weight of casein being less than theweight of pigment to serve as the paint body and the. pigment vehicle inthe ultimate coat of paint, a quantity of a water-resistantwater-insoluble metallic soap in weight less than the casein, and avolatile water-immiscible solvent for the said soap, the soap andsolvent forming a solution homogeneously dispersed in said vehicle toprovide solid soap as a water-proofing agent in the ultimate coat ofpaint.

2. A casein paint composition comprising water as a vehicle, a. quantityof pigment in excess by weight of the amount of water, casein dispersedin the water, a small amount of borax dissolved in the water to maintaindispersion of the casein, the weight of casein being less than theweight of pigment to serve as the paint body and the pigment vehicle inthe ultimate coat of paint, a quantity of aluminum stearate in weightless than the casein, and a volatile water-immiscible solvent ior thealuminumstearate, the solvent and the aluminum steal-ate forming asolution homogeneously dispersed in said vehicle to provide solidstearate as a water-proofing agent in the ultimate coat of paint GTONLEE TANNE.

